Corner clamp



Feb. 28, 1950 J. L. THORNBURG CORNER CLAMP Filed Sept. 4, 1945 mumvrwa JOHN L. THORNBU/ZG- /5 3/ HTTQENEYJ Patented Feb. 28, 1950 UNITED STATES PATENT j OFFICE; .z,49s,725

CORNER CLAW John L. Thornburg, Bremerton, Wash.

Application September 4, 1945, Serial No. 614,207

3 Claims. (o1. i1s99 This invention relates to what are generally referred to as corner clamps and which are designed primarily for the temporary securing of two plates, or the like, in edge to edge position for being joined to form a right angle corner. More particularly, the invention has reference to a clamp for holding two metal plates in a desired right angle relationship for being welded or otherwise joined together along the corner joint.

It is the principal object of this invention to provide a corner clamp of the above kind, whereby plates of different thicknesses may be readily accommodated; whereby the plates may be held securely and rigidly in right angular relationship for being welded together or otherwise secured and without the clamp, as so applied, interfering with the welding of the corner joint.

Another object of th invention is to provide a clamp that readily and automatically adapts itself to use where the plates tobe joined are of difierent thicknesses and wherein the clamping and holding action against both plates is accomplished by tightening of a single thumb screw. I

Still further objects and advantages of the invention reside in the specific details of con-,

struction of parts, in their relationship, mode of operation and use, as will hereinafter be fully described.

In accomplishing these and other objects of the invention, I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings,

whereinp Fig. 1 is a perspective view of a corner clamp embodied by this invention, showing it as functionally applied to two corner forming plates.

Fig. 2 is a top view of the same, with the cover plate of the clamp housing removed for better illustration of the enclosed clamp jaws and the jaw actuating wedge block.

Fig. 3 is a cross section of the clamp taken on line 3-3 in Fig. 2. g

Fig. 4 is a cross section on the angular, line 4-4 in Fig. 2.

Fig. 5 is a perspective view of the clamp jaws and wedge block disassembled from the clamp housing.

Fig. 6 is a perspective view of the clamp housing with cover plate, jaws, wedge block and clamp screw removed.

Referring more in detail to the drawings, the

present clamp device comprises a clamp housing square in shape, equipped along two of its adjacent edges with integral, right-angle side walls II-'II, and at that corner of the plate at which these walls converge, having an integral boss I2 in which an internally threaded bore I3 is formed.

Threaded in the bore I3 is the shank I4 of a clamp tightening thumb screw. The axis of the bore I3 within which the screw is threaded, coincides with a plane that equally divides the right guideways for the clamp jaws as will presently made up of a flat bottom plate I0, substantially 65 end surface 2| be explained.

Overlying the housing that is formed by the plate I0, its side walls II-II and the post I5, is a flat cover'plate I6 that is secured in place by three screws I1. As noted in Fig. 1, two of these screws I! are applied downwardly through marginal ears I8 formed on the cover plate, and threaded into lugs or extended bosses on the walls I I-I I. The third screw is applied through the corner of the plate and into the post I5..

Fitted within the housing and slidable between the bottom wall In and cover plate I6 is the jaw actuating wedge block 20, formed with a flat and converging side surfaces 22-22; 'The block is of the shape of an isosceles triangle, and is disposed with its flat base surface 2| perpendicular to the clamp screw and engaged by the rounded end MD of the screw, as seen in Fig. 2. The side surfaces of the wedge block eachform an angle of approximately with the base surface.

Also, slidably contained between the bottom wall II] and cover plate I6, at the opposite sides of the wedge block 20, are clamp jaws 25-25,

each having a fiat side surface 26, engaged against and slidable on the corresponding side wall II, and a fiat base surface 21 engaged flatly against and easily slidable on a side surface 22 of the wedge block. Each jaw is held in place and guided in its in and out adjustment by the wall II with which it engages and a side surface of the post I5.

It will be understood that by adjusting the thumb screw I4 into the housing while engaged against the Wedge block, the latter will be advanced accordingly, and that the advancing block operates as a wedge that pushes the jaws apart and outwardly from the housing. The jaws are of such length that when the screw 14 is retracted and the wedge block is disposed at its inner limit of adjustment, and the inner end surfaces 21 of jaws seated thereagainst, the outer ends of the jaws will be substantially flush with side edges; of the housing; bottom plate. Hi.

The outer end portions of the jaws are centrally recessed, as at 3B, and flanges 31 project up from the edges of plate I0 into these recessesand springs 32 are held under compression between the flanges and bases of the recesses to push the jaws inwardly so that asthescrew M is retracted, the Wedge block. 2.0., which has no. fixed connection with the screw, will be moved inwardly accordingly.

The cover plate It, as, noted best in Figs. 1 and 4, extends. beyond the outer ends of the jaws; and has.v these edge: portions turned down to form flanges tit-M3,, opposedlycoasting with the outer end, surfaces of the two jaws. These flanges lie in planes that are at. right angles to each other but. at'their near ends, the flanges are spaced apartas noted in Fig. 1, thus to. expose the corner joint. When-1 the, jaws are retracted, there will be; openspaces; between their outer surfaces and the. flanges. and it is into. these spaces, that plate edges are disposed to be held by the clamp.

I Assuming the device to.- be. so constructed, its useis as; follows:

First the two plates that are to'form the corner are brought into. the, desired, relationship; such plates being designated at, A and B in. Figs. 1 and 2,. Then the clamp, with jaws retracted, is appliedt the plates from the. insideof the corner.- thusformed with the top edgesof plates received respectively betweena coacting jaw 25; and flange. in; Then the screw ldistightened against Wedge block 21) and the latter pushed inwardly. As wedge2fi= moves inward-ly,,i.t forcesthe jaws apart and outwardly, each moving out until: its corresponding plate Av or B istightly clamped between the jaw and flange 40.. If. one plate happens to.-

be of greater thickness. than the other, one jawwill, then! come into clamping contact before the. other, but without. detriment because continuedtightening of, the screw id will cause. the wedgev block-ta continue inwardly but with an incident. lateral. shifting that continues to. advance the other jaw until its clamping function. has. been fully accomplished. It is inthe proyisionof. this; ireedomfof, the wedge block for lateral. shifting, thus. to. compensate. for different. thickness, of plates, that an imp rtant feature of the invena tion resides.

With the clamp. so applied, the plates A and B. will. be securely held. for welding or to receive other means of. connection.

When the screw is retracted, the. wedge block is. released, and the two jaws, under the; pressure oi; the springs 32, will be retracted to release the clamp.

Devicesoff this kind. may be made in various.

4 sizes to meet diflerent requirements and may be made 0f various materials.

Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent is:

1. A corner clamp of the character described comprising a housing formed with a pair of relatively rigid flanges outset from the housing and in angular relationship, two guideways formed in the housing and respectively perpendicular to the flanges, clamp jaws mounted in the guideways for movement therein independent of each other toward and from the flanges; said jaws having inner end surfaces in angular convergence, a wedge block slidably contained for advancement in the housing between and slidably engaging said inner end surfaces of said jaws, and free for lateral shifting in the housing relative toits normal line of advancement, a Wedge advancing screw threaded into the housing and engaging the. wedge block to. efiect, an inward .advancementoi the block and an incident clamping; movement of the jaws.

'2'. A clam as recited in claim 1 wherein the wedge block is of the form of an isosceles triangle and has. its opposite side surtaces flatly engaging the inner end surfaces. of said jaws and wherein the. wedge: advancing screw engages in pushing contact with the; inner end surface of said wedge;

. block for its advancement, and spring means acts against the jaws and wedge block with retraction of the screw.

A corner clam-p of: the character described comprising a. housing formed with a pair of rela- '=I tively rigid flanges outset therefrom in right angle relationship, g-uideways formed. in the housing perpendicular to: said flanges, clamping jaws mounted'inthe guideways. for independent movement; from and toward the. corresponding flanges tor the holding of plates placed between them;

said jawsihaving fl'atinner end Surfacesin angular convergence, a wedge block of theform. of an isosceles: triangle, free: for lateral shifting and disposedbetween and having its opposite: side surfaces in sliding contact with the inner end REFERENCES. CITED The following references are of record in the file or this patent:

UNITED STATES PATENTS:

Number Name Date 620,495 Ramseaur, Jr. Feb, 28, 1899 12,659g67'6 Vincent Feb. 21, 1928 2,116,263 Harbaugh May- 3, 1938 

